There's a former police sergeant and FBI cold case task force worker who's on Steven Avery's side. His name is John Cameron, and he believes the person responsible for Teresa Halbach's death is one Edward Wayne Edwards - a serial killer who has previous when it comes to framing other people.
Cameron has been speaking via Uproxx, and he believes that Edward Wayne Edwards "liked to set other people up for the crimes he committed and was obsessed with the media attention surrounding murder. Sometimes he would pick victims based on reports he read in newspapers. Other times his target would be the person being set up for murder, with the victim being almost inconsequential... Officially, Edwards has been convicted of five deaths from 1977 to 1996, including the murder of his adopted son for insurance money. But there’s a growing body of investigators that believe he is responsible for some of the biggest unsolved murder cases in American history. "
In the end, his daughter turned him in to the authorities. Here are just a couple of the theories posed by Cameron which could link him to setting up Steven Avery, see the list in full here: "1) Several of Edward Wayne Edwards’ past victims were murdered on Halloween night. Teresa Halbach disappeared on Halloween night. 2) Edwards had killed in Wisconsin before: In 1980, Edwards mudered Timothy Hack and Kelly Drew in what was later dubbed the Sweetheart Slayings. 2) Edwards was living about an hour away from Steven Avery at the time of the murder."
Meanwhile, the growing number of internet sleuths have unearthed more theories regarding Halbach's death, the latest of which involves the photo widely used throughout the Netflix documentary...
According to Rolling Stone, the internet has noticed that Halbach was carrying a bunch of keys, not just one. Anyone who's seen the documentary knows what this suggests.
— Andrea Lukowski (@andrea_lukowski) January 21, 2016
Of all the new theories and findings, Avery's 2006 defence lawyer Jerry Buting said: “We were only two minds. What I’m discovering is that a million minds are better than two. Some of these people online have found things with a screen shot of a picture that we missed."